Polymerization catalysts offer opportunities for providing new processes and products to the markets. In particular, olefin polymerization catalyst systems are of great interest in making new products available.
One method of evaluating polymerization catalysts is to collect polymerization data in a laboratory and/or pilot plant setting using the polymerization catalyst under polymerization conditions in actual reactors. Polymerization activity measurements and analysis of polymers produced may then be used to determine catalyst activation, activity profile, and the like. Information obtained from actual polymerization may also be used to guide development of new catalysts and/or to guide in the scale up of catalysts systems in manufacturing processes.
Spectroscopic methods of analysis may also provide information about catalysts, for example: elemental analysis and imaging methods such as secondary ion mass spectroscopy (SIMS) and X-ray phosphorescence (XPS) may be used to determine various spatial distributions within a catalyst system, including metal loading on a catalyst support.
Ultraviolet/Visible absorption spectra (UV/Vis) is reported as being useful in determining the activation of a homogeneous catalysts system. It has been reported that the activation process can be followed by changes in the absorption bands in the UV/Vis spectra. (see for example D. Coevoet, H. Cramail, and A. Deffieux, Macromol. Chem. Phys. 199, 1451-1457, 1998; J. N. Pedeutour, D. Coevoet, H. Cramail, and A. Deffieux, Macromol. Chem. Phys. 1215-1221, 1999; A. Deffieux, Macromol. Chem. Phys. 199, 1459-1464, 1998;
It has been reported that MAO activation of zirconocene proceeds in more than one step, and that distinct absorption bands may be observed for each chemical species using UV/Vis (see for example U. Wieser and H.-H. Brintzinger, “UV-VIS Studies on the Activation of Zirconocene-Based Olefin-Polymerization Catalysts”, in Organometallic Catalysts and Olefin Polymerization. Catalysts for a New Millenium R. Blum, A. Follestad, E. Rytter, M. Tilset, and M. Ystenes, eds. Springer, 2001.)
It has also been reported that 1H and 13C NMR can be used to probe the chemistry of activation for homogeneous catalysts. These reports are directed to studies used in a research mode to infer the structure of the activated metallocene and to investigate the kinetics of the activation. See for example, Landis et al., JA036393u.
However, such analysis does not provide detailed information of the chemical state of the catalyst, in particular the activation of the catalyst for metallocene containing catalyst systems. Nor do the methods provide information as to activation of supported catalyst systems. Accordingly, the need remains for a method of determining the chemical state of the catalyst, and in particular the activation of supported metallocene catalyst systems. Furthermore, the need exists for a method to determine the activation of a catalyst system, which can be practiced in either the manufacture of catalysts or for quality control in on-going commercial polymerization activities including manufacturing of various polymers.